(a) Production test plates must be provided for Class I, Class I-L, Class II, and Class II-L pressure vessels are specified in this section.

(b) Main power boilers must meet the test plate requirements for Class I pressure vessels.

(c) Test plates are not required for heating boilers or Class III pressure vessels. Test plates are not required for main power boilers or pressure vessels constructed of P1 material as listed in QW/QB 422 of Section IX of the ASME BPVC (incorporated by reference; see § 57.02-1) whose welded joints are fully radiographed as required by part 52 or 54 of this subchapter as applicable except when toughness tests are required in accordance with § 57.06-5. When toughness tests are required, all prescribed production tests must be performed.

(a) At least one set of production test plates must be welded for each Class I or Class I-L pressure vessel except as follows:

(1) When the extent of welding on a single vessel exceeds 50 lineal feet of either or both longitudinal and circumferential joints, at least one set of test plates must be welded for each 50 feet of joint.

(2) When the extent of welding on vessels welded in succession exceeds 50 lineal feet of either or both longitudinal and circumferential joints, at least one set of test plates must be welded for each 50 feet of aggregate joint of the same material where the plate thicknesses fall within a range of one-fourth inch. For each 50-foot increment of weld, test plates must be prepared at the time of fabrication of the first vessel involving that increment.

(b) Production test plates for Class II-L pressure vessels must be prepared as for Classes I and I-L vessels except that the provisions of paragraphs (a)(1) and (2) of this section are applicable to each 150 lineal feet of welded joint in lieu of each 50 lineal feet.

(c) In the case of Class II pressure vessels, no more than one set of production test plates need be prepared for each 300 lineal feet of either or both longitudinal and circumferential joints. In the case of single vessel fabrication, a set of test plates is required for each 300 lineal feet of weld or fraction thereof. In the case of multiple vessel fabrication where each increment of 300 lineal feet of weld involves more than one pressure vessel, the set of test plates must be prepared at the time of fabrication of the first vessel involving that increment.

(a) Except as otherwise specified in this section a test plate must be attached to the shell plate on one end of the longitudinal joint of each vessel as shown in figure 1 to § 57.06-3(d), so that the edges of the test plate to be welded are a continuation of and duplication of the corresponding edges of the longitudinal joint. For attached test plates, the weld metal must be deposited in the test plate welding groove continuously with the weld metal deposited in the groove of the longitudinal joint. As an alternate method, the marine inspector may permit the use of separate test plates, provided the same welding process, procedure, and technique employed in the fabrication of the longitudinal joint are used in welding the test plates.

(b) All test plates, whether attached to the shell or separate in accordance with paragraphs (a) and (d) of this section, must be prepared from material of the same specification, thickness, and heat treatment and, for Class I-L and Class II-L vessels, the same heat as that of the vessel for which they are required. However, except when required to be from a specific heat, test plates may be prepared from material of a different product form, such as plate in lieu of a forging, provided the chemical composition is within the vessel material specification limits and the melting practice is the same.

(c) Test plates are not required for welded nozzle attachments.

(d) In the case of vessels having no longitudinal welded joints, at least one set of test plates must be welded for each vessel, using the circumferential joint process, procedure, and technique, except that the provisions of § 57.06-2(a) also apply for Classes I and I-L vessels, and that the provisions of § 57.06-2(a) and (c) also apply for Classes II and II-L vessels.

(e) Test plates must be made by the same welder producing the longitudinal and circumferential joints. If more than one welder is employed in the welding of the pressure vessel(s), the test plates must be made by the welder designated by the marine inspector. The test plates must be of the same thickness as the material being welded and must be of sufficient size to provide two specimens of each type required, except that in the case of pressure vessels having no longitudinal seams, the test plate need be only of sufficient length to provide one set of test specimens, and if a retest is necessary, an additional set of test plates may be welded separately.

(a) For test plates three-fourths inch or less in thickness one reduced section tensile specimen and two free-bend specimens must be tested. For plates exceeding three-fourths inch in thickness one reduced section tensile specimen, one free-bend specimen and one guided side bend specimen must be tested. In addition, boiler drums of thickness five-eighths inch or greater must have a tension test specimen of the weld metal as required by paragraph (f)(2) of this section. Toughness tests are required for Classes I-L and II-L pressure vessels as specified in § 57.06-5.

(b) The test plates must be so supported that the warping due to welding does not throw the finished test plate out of line by an angle of over 5°.

(c) Where the welding has warped the test plates, the plates must be straightened before being stress-relieved. The test plates must be subjected to the same stress-relieving operation as required by this subchapter for the pressure vessel itself. At no time must the test plates be heated to a temperature higher than that used for stress-relieving the vessel.

(d) The bend specimens must be taken from opposite sides of the reduced-section tensile specimen in their respective test plates as shown in figures 1 and 2 to § 57.06-4(d).

(e) In submitting the samples for test the manufacturer must state the minimum and maximum tensile range of the base metal.

(f) The external appearances of the welds and the amount of weld reinforcement shall conform to the requirements for fabrication, and the maximum reinforcement for the test plates must not exceed the maximum permitted for construction.

(1) The tension-test specimen of the joint must be transverse to the welded joint and must be of the full thickness of the plate after the weld reinforcement has been machined flush. The form and dimensions must be as shown in figure 3 to § 57.06-4(f). When the capacity of the available testing machine does not permit testing a specimen of the full thickness of the welded plate, the specimen may be cut with a thin saw into as many portions of the thickness as necessary, as shown in figure 4 to § 57.06-4(f) each of which must meet the requirements. The tensile strength of the joint specimen when it breaks in the weld must not be less than the minimum of the specified tensile range of the plate used. If the specimen breaks in the plate at not less than 95 percent of the minimum specified tensile range of the plate and the weld shows no sign of weakness, the test is considered acceptable.

(2) Boiler drums fabricated of plate of thicknesses of five-eighths inch or greater 2 to § have a tension-test specimen of the weld metal machined to form as shown in figure 5 to § 57.06-4(f) taken entirely from the deposited metal. The all-weld tension test specimen 2 to § have a tensile strength of not less than the minimum of the range of the plate which is welded and 2 to § have a minimum elongation in 2 inches of not less than 20 percent.

(g) The freebend specimens must be of the form and dimensions shown in figure 6 to § 57.06-4(g). For plates of three-fourths inch or less in thickness one of the specimens must be bent with the face of the weld in tension. Each freebend specimen must be bent cold under freebending conditions until the elongation measured within or across approximately the entire weld on the outer surface of the bend is at least 30 percent, except that for Class II and Class II-L pressure vessels, the minimum elongation must be 20 percent. When the capacity of the available testing machine will not permit testing a full thickness specimen, the specimen may be cut with a thin saw into as many portions of the thickness as necessary as shown in figure 4 to § 57.06-4(f), provided each such piece retains the proportion of 1.5 to 1, width to thickness, each of which must meet the requirements. Cracks at the corners of the specimens or small defects in the convex surface, the greatest dimensions of which do not exceed one-sixteenth inch need not be considered as failures.

(h) The guided-bend specimen must be bent with the side of the weld in tension, its width must be equal to the full thickness of the plate and its thickness, after machining, must be 0.350 inch to 0.380 inch to permit bending in a jig having the contour of the standard jig as shown in Figure QW 466.1, QW 466.2, or QW 466.3 of Section IX of the ASME BPVC (incorporated by reference; see § 57.02-1). The specimen must withstand being bent cold to the full capacity of the jig without developing any crack exceeding one-eighth inch in any direction. Where the plate thickness exceeds two inches, the specimen must be cut in two so that each portion does not exceed 2 inches in width. Each such portion must be tested and must meet the requirements.

(i) One retest must be made for each of the original specimens which fails to meet the requirements. Should the retests fail to meet the requirements, the welds which they represent must be chipped out, rewelded and new test plates provided.

(a) In addition to the test specimens required by § 57.06-4(a), production toughness test plates must be prepared for Classes I-L and II-L pressure vessels in accordance with subpart 54.05 of this subchapter.

(b) For nonpressure vessel type cargo tanks and associated secondary barriers as defined in § 38.05-4 of subchapter D of this chapter, production toughness test plates must be prepared in accordance with subpart 54.05 of this subchapter.